User's Manual

Working in Professional mode
51
The following parameters must be stated in order to define the measuring window:
Parameter Description
Measurement
(from … to)
Beginning and end of the daily measuring window.
Select from: 0:00 to 24:00 hours
Default: 2 a.m. to 4 a.m.
Explanation: The logger performs measurements and saves the
measurement values within the stated window. Interference from
background noise (traffic, water use, etc.) should be at a minimum at
this time.
Values per
measuring
window
Number of saved measured values per day.
Select from: All 100 measured values or the 50/20/10/5 lowest values
of the measuring window
Default: 50
Explanation: A logger performs 100 measurements in each measuring
window. A maximum of 100 pairs of values (noise level and frequency)
can be saved in the internal memory. The pull-down menu is used to
specify whether all 100 measured values in the logger are to be saved
or just the lowest 50/20/10/5 values in the period.
If, for example, “100 pairs per measuring window” is specified, the
logger must be read after each measuring day so that no measured
data is overwritten in the subsequent day.
If “20 measurement values per measuring window” is specified, the
logger only has to be read after 5 measuring days.
Leak
threshold
value
Noise level from which to classify a noise as a leak.
Select from: 0 to 60 dB
Default: 10 dB
Explanation: If the lowest measured noise level in a measuring period
is above this threshold, this is an indication to the user that there is a
leak in the pipe system. Loggers where the threshold is exceeded are
pointed out in particular during the data read-out and analysis.
Experience shows that it is often sensible to have a value of
10 dB as the leak threshold.
In order to gain an impression of the average noise level in the
pipe and to gauge whether the default leak threshold of 10 dB
is too high or too low, one possibility would be to perform a real
time measurement before programming the loggers at the
place of use (see page 58).
If, during the first few measuring days, the selected leak
threshold is always far too low or far too high, you should once
again reprogram the loggers concerned and adjust the leak
threshold.
Measuring
days
(Mon to Sun)
Days of the week when measurements are to be taken.
Select from: Monday to Sunday
Default: Monday to Sunday
Explanation: No measurements are performed on the other days.
Measuring parameters